A Detail Altered
by Bookaholic27
Summary: In 2014, the Croatoan virus rages on and Lucifer has nearly conquered the earth. In 2015, the Darkness has been unleashed and Death is dead. Chuck knows something's up. With his visions beginning renewed, himself and the mysteriously resurrected Dean and Cas must navigate the echoes of an alternate timeline in order to find a way to save their own. Set post 5x04 and up to s10/11
1. Chapter 1

**Set in Endverse after Past Dean leaves. Chuck has begun to have visions of how events have occurred in the canon universe of Supernatural.**

 **This story can be seen as somewhat like a Read the Books story because excerpts from throughout seasons 5 to 10 (and maybe even 11) will be read by the characters and commented upon. Because of this, there are spoilers for the whole series up to the present here. Especially in this chapter, if you have not watched the season 10 finale, I'd suggest not reading this story just yet.**

 **If someone would like to review a scene they want the endverse characters to read about, I'd be happy to put it in. Just know that I'm not doing full episodes and I'm not going to focus too much on season 5 (for plot reasons).**

 **Just know that the story will involve much more than the reading, and may even involve a few surprise meetings later.**

 **This is a work in progress and updates are likely to be irregular. I hope you all enjoy and feedback is definitely appreciated.**

 **Disclaimer: No, I don't own Supernatural**

BANG!

The shot reverberated through Dean's head as he exited the van. He could still feel his finger on the trigger. He'd felt no hesitation. He was long past that. It had only been for maybe a millisecond, but it had felt like he was on the precipice of a new day. A better one. The end of, well, the end. What a fucking joke.

Dean's neck ached as he headed towards his cabin. He felt the presence of curious eyes burning into his back, but his own eyes stared stonily ahead. What he wanted more than anything was to just pass out for a couple of weeks. Or years. Let someone else deal with the crap hole they called a planet for once. He was tired, but he'd be lucky if he got maybe four hours before he had to figure out the impossible, mind numbing question of where they went from here.

It looked like even when all hope had been stomped over like road kill, Dean would never catch a break.

Out of the corner of his eye, Dean saw as Cas ghosted into his own cabin, shoulders slumped and likely off to shoot up with some more crap. Dean honestly had no idea how he had survived. How either of them survived, really. He'd felt the pressure of Lucifer's foot on his neck. Something had snapped. He'd died and he'd sent Cas off to his own death. Yet somehow, here they were. Everyone else was dead.

He wasn't sure if it even mattered anymore.

"Dean!" Came a familiar, if stressed, voice.

Dean suppressed a groan, "Not now, Chuck."

The prophet was panting heavily, as if he'd run across the whole camp just to find him. His dark hair was ruffled and messy. Below his eyes were dark, tired circles. Those eyes were now staring at Dean with an intensity that the hunter hadn't been sure Chuck was capable of.

"I need to show you something," he said, his eyes glinting manically.

Dean didn't care what Chuck's problem was. It could wait a few hours. Continuing his brisk pace back to his cabin, Dean called over his shoulder to the prophet who was no doubt struggling to keep up.

"I really can't do this right now, man." Even Dean was surprised by how defeated he sounded.

Still, Chuck's response came at rapid fire, "I'm sorry Dean, but this can't wait."

Reluctantly, Dean turned to face the shorter man. "Fine. What is it?"

"Come with me."

SPN SPN SPN

Chuck's cabin was a mess. Where he was usually organized and practical when planning for supply runs and keeping general order in camp, his living space clearly didn't show it. It was surprising, considering the very small amount of personal possessions that those of Camp Chitaqua often kept. The meager bed sheets and pillows that Chuck had allotted himself were sprawled about haphazardly. Stacks of paper littered the floor, some of it appeared to be lists and records that Chuck had kept over the years. Others looked like old manuscripts from the Supernatural books.

"Okay," came Dean in a hard tone, "What is it? What did you wanna show me?"

Chuck fiddled through his stacks of paper, looking jittery. After a minute, he pulled a thin pile from the mess and handed it to Dean. Chuck gave the hunter an encouraging look, glancing at the sheets in expectation.

Dean just raised his eyebrows. "Do I have to read the whole thing?"

The prophet shook his head, "Just flip to a random page. I'm sure you'll get the idea."

Sighing, Dean flipped the manuscript open to the last page. Eyes darting down to Chuck's messy scrawl, he began to read.

 _Sam stepped out of the bar, followed closely by Dean. He looked up to the sky as if in prayer and a relieved sigh came from the younger Winchester, telling a tale of bone-deep exhaustion. It was finally over._

 _"This is good, Dean. This is good," said Sam, glancing over at his brother. "The mark is off your arm._ _Nothing crazy happened."_

 _Things were finally going their way for once. Of course things weren't perfect. Death was dead and Sam knew that whatever that meant, it couldn't be good. Still, they were Winchesters. They could handle whatever came next. Together._

 _Feeling around, Sam pulled out the keys that had been burning a hole in his pocket for hours._ _"You get your baby back," Sam said reassuringly as he handed the jingling things back to his_ _brother._

 _Dean accepted them, still looking tense, his eyes on the ground._ _"Yeah," the blonde answered, looking up, "I'm sure everything's perfectly fine."_ _There was that look in his eyes. Like he was just waiting for shit to hit the fan again, but was just too tired to care. Sam couldn't blame him. They'd both been through hell this past year. Thankfully, that was figurative this time, but Charlie's death and Dean's time with the mark would surely haunt_ _them both._

 _The pair headed away from the empty bar and Sam placed his hand on Dean's shoulder. He knew it wouldn't help much, but he hoped that he could at least offer some form of comfort._

 _Abruptly, a harsh boom disrupted the quiet scene._ _Startled, Sam tensed, his hand jerking away from his brother._ _The noise lapsed into a strange crackling and the two quickly looked up in search of_ _the source._

 _"What the-" Sam gasped as red light streaked across the previously clear sky._ _With a crash, the first streak of lightning struck down. More followed, swift and random, as strangled thunder echoed around the field._ _The brothers just stood, dumbfounded, as the onslaught raged on._

 _And then finally, it was over. Everything was silent._

 _It didn't take Sam long to put the pieces together._ _"What did Death call this?" He asked nervously, hoping to anything that would listen that he was wrong._

 _Dean offered no such relief. "The Darkness," he said forebodingly._

 _And as if things weren't bad enough as it was, the ground began to shake._ _Sam and Dean looked down just as black smoke burst from the ground beside them. The two_ _looked on in horror as other chains of smoke began to erupt, soaring over their heads and assembling at a further point in the field in a thick black mass._

 _Sam gaped. What the fuck!_

 _"Get in the car," came Dean's panicked voice, "Lets go! Let's go!"_

 _They simultaneously rushed towards the Impala, slamming the doors shut as fast as they could._ _Sam saw as Dean slid the key into the ignition, feeling cold. His brother backed up, but they were soon_ _brought to a screeching halt._ _The car groaned as Dean slammed on the gas, and Sam felt as his brother opened the car door in order to take a look at the problem._ _It was too late, Sam knew. They'd landed themselves in a freaking pothole, and now this "Darkness" was going to kill them._

 _Sam stared straight ahead, watching the black mass role towards them like a tidal wave._

 _"Dean," Sam uttered, clutching Dean's shoulder._

 _The Darkness consumed everything in its path._ _His brother slammed the car door shut as the wind howled around them._ _Sam clutched at the impala as they both stared in apprehension at the oncoming force._

 _It was almost upon them. Sam's eyes widened._ _"Dean!" he shouted._

 _The smokey mass enveloped the car._

 _Everything went black._

Dean looked up from the manuscript, chest tight. "What the hell is this?" He let out, teeth clenched.

Chuck just nodded giddily, "I know!"

Dean sighed, "No, I mean seriously man. What the fuck? You're writing fan fiction now? I mean I know it's the apocalypse, but really? I didn't think you'd stoop that low."

"Wait, what?" Chuck stuttered. Quickly though, the prophet's eyes widened in realization. "Oh! No, no, Dean. It's all real."

Dean snorted. "Really, huh? Because I think I would notice if I was suddenly 'enveloped by darkness' or whatever. Besides, Sam is the Devil right now. It's kind of a problem we've been dealing with for the past couple of years. I'm not sure if you remember."

Dean might have been getting a bit too worked up about the stupid story, but Chuck should cut him some slack. He'd just failed in their only chance at icing the devil. Had waisted five years on a pointless mission. Hell, odds were that he'd recently died and been brought back again. He didn't need more crap to deal with.

"Are you done?" Chuck asked with raised eyebrows, uncharacteristically snappy.

"Are you?" Dean bit back, shoving the manuscript still clenched in his hands back at the prophet.

The shorter man just stared at him, waiting.

Dean had to give the guy some credit. Most people rarely bothered to pick fights with him anymore. Maybe they respected him. Maybe they were just so done with it all that they barely cared anymore. Cas made an effort sometimes. He questioned some of Dean's more outlandish plans, but for the most part he just went with whatever ideas Dean settled upon. Risa was an exception, Dean guessed. She never hesitated to challenge him. And now she was gone like all the others.

Dean gave in. Might as well get this over with.

"Go on," he prodded unenthusiastically.

Chuck shuffled his feet nervously, reticent all of a sudden.

"Chuck," Dean growled, irritated.

"I've been having dreams again," came Chuck's rushed response.

Dean blinked, "What? You mean like...psychic dreams? Like the kind you had when you were writing about my life?"

Chuck nodded furiously, "Exactly!"

Having overcome his initial shock at the admission, Dean glanced over the prophet skeptically. "So you're saying that what I just read is my future?"

Chuck's words stumbled a bit, "Well...no. I think it's the other Dean's actually."

"The other Dean's?" Dean repeated quizzically.

"Yes," Chuck confirmed, "Past Dean from 2009."

Dean couldn't believe what he was hearing. "Look, Chuck," he said slowly, trying his best to remain calm in the outset of a raging headache, "I can see you must be...pretty enthusiastic about this, uh, theory of yours, but you do know that Dean from 2009 will eventually become me, right? 2014 me. Are you sure you're not just having, you know, actual dreams?"

"That's what I thought at first too, but they were just so vivid," replied a once more jittery Chuck, "and they felt exactly like the visions from before. I know that-"

"Wait, at first?" Dean cut in.

"Oh," answered Chuck, looking sheepish, "Yeah, they starting happening a day or two before Past Dean showed up."

Dean huffed, running a hand through his hair in frustration, "And you didn't think sharing with the class would be a good idea?"

Chuck rolled his eyes, "Like I said, I didn't believe in the dreams at first either. Besides, we had a lead on the Colt! It didn't seem like a good time."

"Yeah, well look how good that turned out," came Dean bitterly.

They both went silent, the weight of the losses the day had brought still sinking in.

Chuck cleared his throat, "So I think he changed something."

Dean's own throat felt raw, "What?"

"I think that maybe Past Dean saw something here in our time and ended up changing his future."

Dean raised his eyebrows, "Wouldn't that mean that all of us shouldn't exist anymore? Besides, you haven't had any prophet-dreams in years. Why would that change now?"

Chuck nodded emphatically, "No idea, but it's exactly the sort of thing we should probably ask Cas."

Chuck and Dean had been standing in the middle of the cabin for nearly 15 minutes, arguing over a stupid manuscript. They had accomplished nothing. Dean felt like pulling his hair out. "So why didn't you just ask him first before coming to me with this?" asked Dean severely, "We have more questions than answers."

Chuck hesitated, "You're better at dealing with him when he's like this."

"Like what?" Dean demanded. He already knew the answer though. Him and Cas were the lone survivors of their mission, and while Dean was shaken by what had happened, he knew that Cas must have been infinitely worse. Probably getting killed by the Devil? Well it wasn't like Dean hadn't died before. Cas had watched as his most skilled colleagues were taken down around him. A part of Dean thought it might've even been better if he'd been killed by the Croats as well. At least then there would be less misplaced guilt on Cas' part. Dean knew very well where that guilt should really lie.

So they both knew the real answer.

"High off his ass," Chuck said instead.


	2. Chapter 2

**I figured I'd get this out to you guys quickly, since it's more of a filler chapter.**

 **By the way, I forgot to mention this last chapter. I'm going to be referring to Endverse!Cas as "Cas" and canon!Cas as"Castiel".**

 **I don't have a beta reader, so though I'm trying to keep this error free, there will most likely be mistakes. Feel free to tell me about them. I'll try my best to fix it if I can. Also, I've been told that I have a tendency to make Endverse!Cas kinda OOC. If I'm doing that here, let me know so that I can figure out what needs correcting.**

Thank God there were no women today. Dean didn't think he had the patience to deal with Cas'...well, whatever the hell it was that he did in here. Nope. For now, he was just high. On any normal day, Dean could easily say that it was his fault for the downward spiral Cas had taken. Today, Dean was blameless. Mostly because if things had gone as planned, Cas would be dead right now.

"To what do I owe the pleasure?" asked the ex-angel, unfocused eyes looking towards the pair who had entered his cabin unannounced. Sprawled out on his bed, Cas looked to be the picture of decadence. Dean knew better though. He could easily see the deep sorrow that lay underneath the smirk. The same slump to his shoulders that Dean was sure he mirrored perfectly.

"Read," Chuck said, abruptly handing over his manuscript.

Cas raised his eyebrows, but took the papers without question. It took him a bit longer to read than Dean, understandably so if the smell wafting off of the man was any indication. After a few minutes, he sat up and silently handed the pages back to Chuck, expression sober.

Tapping his foot, Chuck looked expectantly at Cas. Cas stared back.

"Well?" asked Chuck impatiently.

"Well, why do you need me?"

"I think it's a vision. From the angels or God or whatever," Chuck replied and gesturing to himself and Dean, continued, "We figured you would know if that's even possible. I mean, the angels jumped ship after all and my dreams haven't been back for years."

Cas looked between the two contemplatively, "Huh. I guess it's a good thing I didn't die today."

Silence followed.

For a split second, he looked at Dean knowingly before turning back to Chuck. Dean thought he might have imagined it, but there it was. The budding suspicion that Dean had harbored throughout their trip back to Camp Chitaqua. Did Cas know he had been bait? He hadn't complained much about the mission. Not more so than usual, anyway. Still, he'd seemed quiet. At the time, Dean had thought it was because of his younger self and whatever can of worms he may have opened up. On the way back to camp however, the odd behavior had continued. Dean doubted that anyone else would've noticed it, but Cas had been Dean's oldest friend. Even if he wasn't sure if they could still be considered that. Dean hoped that Cas didn't know, but his hopes rarely turned out. He tried to ignore why that thought seemed to hurt so much.

Dean finally broke the silence, explaining quickly all that Chuck had already told him, seeing as the prophet didn't look like he was going to.

"Interesting," Cas said way too calmly, "but useless."

"Their prophetic visions!" Chuck protested.

"Or some supernatural creature decided to play a prank on you. Trust me, I've heard of 'the Darkness,' and it's just a myth. I doubt that even in some alternate universe it could be released."

Chuck jumped on that, "So you admit this could be an alternate universe!"

Cas sighed, running a hand through his already messy hair, "Of course it _could_ be. If it was only created by whatever Past Dean saw here, our dimension would have to continue existing in order to keep the balance."

"Hold up a minute, Cas," Dean interrupted, his head whirling, "What's the Darkness anyway?"

Cas shrugged, "It's nothing. Just some horror story that angels used to tell each other."

Dean waited for him to continue. Exasperated, Cas nonetheless did as urged, "According to the story, the Darkness existed before God. It was a force of untold evil. God and the archangels fought against it and only barely won, locking it away forever."

Dean raised his eyebrows, "Sounds bad, I guess."

"Oh, it was bad," Chuck cut it, hands gesturing wildly, "In my dream after things cut to black, I felt this horrible...wrongness. I almost threw up."

Cas' hand went to his chin as he looked off to the side ponderingly, "I suppose that if you _were_ having visions, it would make sense for them to have started up now. Past Dean only changed things when he actually came here after all. Zachariah may have accidentally reforged your connection to heaven. It would've had to have been a major change though..."

"Major change?" Dean repeated, "Why?"

"Because if whatever decision he made differently only altered one or two things, the reality wouldn't be powerful enough to filter into Chuck's dreams. Whatever change Past You made was big," Cas replied, reaching over to his desk to grab for a jar of pills.

"Like...apocalypse big?" asked Chuck hesitantly.

"Who knows," Cas shrugged, dry swallowing several of the unnamed pills, "Lucifer might not even have won. Maybe there was no Croat outbreak. Maybe Dean said Yes."

Well that sounded like a friggin dream. Dean had spent years wishing he'd made that call, had tried to instill the idea in his younger self, but he hadn't actually believed Past Him would do it. Dean knew himself and he was too damned stubborn. Still if it was true, then he guessed he should be happy that there was at least one world out there that wasn't entirely screwed over. But then again...

"Can't be that great a universe if this Darkness thing was apparently unleashed."

Something wasn't right about that though. After all, in Chuck's manuscript, the other Dean certainly didn't seemed possessed by Michael. Sam was fine as well, and they both had even seemed close again. If Michael _had_ won, then that world was a piss poor excuse for paradise. So Dean figured the question was, did Lucifer still possess Sam and for some reason let him go? Did Michael possess Other Dean and do the same?

Unless...neither happened.

"Chuck, what dreams have you had so far? What do you know?" Dean asked urgently.

"Um..." Chuck fumbled, "a lot of them were pretty vague and confusing. Out of order too, I think." Chuck seemed to be wracking his brain, "There was one where Cas was with some bees." He paused for a moment in thought. "Well...a lot of bees, actually." he amended, "He seemed pretty calm about it though."

"Chuck!"

Chuck put his hands up, "Okay, okay," he mollified, "Uh...in one you, erm, the other you was singing karaoke. Oh! And Sam hit a dog."

"Sam hit a dog?" Cas asked curiously.

Chuck nodded, "Yeah, that one was actually pretty vivid. Sam was all _this is an animal hospital! You save animals! Save this animal!_ I mean, he looked really freaked out. And then Amelia said-"

"Whose Amelia?" came Cas.

"The veterinarian," Chuck replied, "So Amelia said that-"

Dean groaned, "Would you two forget about the stupid dog?"

They both looked up at Dean.

"Do you know anything actually useful, Chuck?" Dean muttered through clenched teeth.

"Why do you think I showed you _that_ manuscript?" Chuck began, " It has the most info. I mean, just the things that Sam was thinking in the passing were crazy enough. Did you not notice when he said that Death was dead?"

"Maybe he was being figurative," Cas piped up.

"I don't think that was figurative," said Chuck seriously. The prophet looked back to Dean questioningly. "Why are you suddenly so interested?"

Dean stared intensely at the pair in front of him, "Don't you see? This is it! Our last chance to make things right."

"Dean...what are you thinking?" asked Cas suspiciously.

"I'm thinking that no one's being possessed by an archangel in Chuck's dreams. Some other me is apparently out there singing karaoke. Fucking veterinarians still exist! Don't you guys get what that means?"

Understanding flickered across both of their faces. Chuck's eyes widened, "No apocalypse. Like at all?"

Dean felt jittery, "Only up to whatever '09 me knew. After that...hell, who knows! But if we can find out how he did it, maybe we might finally get a real shot at icing the Devil."

"We spent 5 years on our last 'shot,' Dean," Cas warned.

Dean knew that of course. He knew that by this point, he should've been drowning his woes in a bottle of whatever cheap liquor they'd managed to salvage on the last raid. Everything they'd worked for had been for nothing. All of the sacrifices that Dean had made? Pointless. More than all of the feelings of self pity swirling inside him though, there was a drive that he had to set things right somehow. It was the only cause he had left in the world. His only purpose. He had to fix what he and Sam had started. It was an impossible task. Maybe more-so than it had felt like before, but for some reason, Dean felt lighter than ever. He figured it was best not to name the feeling, because it seemed remarkably close to hope.

Dean grinned. It felt odd on his face. "Well, I guess we should hurry up this time, huh?"

Cas gave him a tired look, "Fine. Let's find out how badly our alternate selves screwed up their universe, shall we?"

Chuck cleared his throat awkwardly, "I, uh, haven't had any dreams about killing Lucifer, Dean."

Dean just nodded, "Then lets get some shut-eye. I don't know about you, but I could sleep for 3 days."


End file.
